【摘 要】
：
This work provides numerical and experimental investigations of blanking process,where the shear-en-hanced Lemaitre\'s damage model is fully characterized and successfully applied in blanking process to predict the cutting force and cutting edge geometr
【机 构】
：
Department of Vehicle Engineering,College of Engineering,China Agricultural University,Beijing 10008
论文部分内容阅读
This work provides numerical and experimental investigations of blanking process,where the shear-en-hanced Lemaitre\'s damage model is fully characterized and successfully applied in blanking process to predict the cutting force and cutting edge geometry under different blanking process parameters.Advanced high strength steel DP1000 and an aluminum alloy A16082-T6 are selected for series of experiments.To obtain the damage parameters in Lemaitre\'s damage model the fiat rectangular notched specimens tensile test was conducted and the inverse parameter identification procedure was performed.For characterizing the crack closure parameter h in the shear enhanced Lemaitre\'s damage model,an in-plane torsion test with novel specimen design was conducted.The finite element model (FEM) of this test was established with the minimum mesh size of 0.01 mm which was consistent with the minimum mesh size in the shear zone of the FEM for blanking process simulation.The longitudinal strain dis-tributions of four kinds of initial notch radius or central-hole specimen were measured and compared with simula-tion results to validate the FEMs for these four tests.Deformation analysis of blanking of a circular work piece also was performed under three clearances.The effects of blanking conditions on sheared part morphology were detected.Stress triaxiality distribution of the blank sheet was revealed taking advantage of the successfully established FEM.The availability of the testing method and the determination method of the parameters was investigated.
其他文献
The machining accuracy of computer numerical control machine tools has always been a focus of the manufacturing industry.Among all errors,thermal error affects the machining accuracy considerably.Because of the significant impact of Industry 4.0 on machin
目的 姜黄作为药食同源物质之一在我国被广泛使用,基于安全性的考虑,有必要对姜黄进行健康危害评估.方法 本文基于系统文献检索(Systematic Literature Searches,SLS)方法,收集姜黄的有效毒理学数据,开展其危害评估.结果 姜黄素在动物及人体内吸收入血快,主要分布在肾、肝和肠道中,粪便为主要排泄途径.姜黄急性毒性属实际无毒,小鼠经口LD50＞100g/kg.bw.亚急性、亚慢性毒性试验显示姜黄会引起实验动物肝、肾和脾局灶性坏死.慢性毒性动物实验显示,长期使用姜黄会引起胃肠道非肿瘤性
目的:观察人文护理关怀方法对肾结石患者健康知识与护理满意度的影响.方法:选择62例肾结石手术患者作为研究对象,按护理措施将其分为对照组和观察组,将接受常规护理措施的30例患者作为对照组,将接受人文护理关怀的32例患者作为观察组.比较两组患者干预后的健康知识掌握情况和护理满意度.结果:干预后,观察组的健康知识掌握平均分和护理满意度平均分(87.32±5.26)分、(96.23±7.01)分均明显高于对照组的(65.72±4.36)分、(96.23±7.01)分(P＜0.05).结论:人文护理关怀能增加肾结石
Following recent insights on structure-cell-function interactions and the critical role of the extracel-lular matrix (ECM),the latest biofabrication approaches have increasingly focused on designing materials with biomimetic microarchitecture.Divergence e
目的 对SD大鼠垂体自发性病变Rathke裂囊肿发生情况进行观察分析,获得安全性评价试验中SD大鼠的背景病变资料.方法 收集近2年完成的10项90天经口毒性试验中的对照组及高剂量组动物,共计400只17～19周龄SD大鼠,雌雄性别各半,对各只动物的垂体病理切片在光学显微镜下进行组织学观察,对Rathke裂囊肿进行诊断并统计其发生率.结果 在总计400只SD大鼠中,共报告10例Rathke裂囊肿,总体发生率为2.5％.在200只雌性SD大鼠中报告4例,发生率2％;在200只雄性SD大鼠中报告6例,发生率3％
目的:探讨常规尿检验和生化检验在糖尿病诊断中的应用价值.方法:选取2019年2～2020年2月收治的116例糖尿病患者,依据患者入院顺序编号后奇偶数分成A组和B组,A组患者接受常规尿检验,B组患者接受生化检验,分析对比患者的检查结果,得出结论.结果:58例A组患者使用常规尿检验的准确率为82.76％;B组58例患者中使用生化检验的准确率为91.38％;B组检验的准确率明显高于A组,数据差异对比具有统计学意义(P＜0.05).结论:常规尿检验与生化检验均能检出糖尿病患者病情,但生化检验操作简便,准确率更高,
Imaging through a time-varying water surface exhibits severe non-rigid geometric distortions and motion blur.Theoretically,although the water surface possesses smoothness and temporal periodicity,random fluctuations are inevitable in an actual video seque
目的 探讨父亲职业性接触农药与儿童白血病的关系.方法 检索万方、维普、CNKI、Cochrane library和PubMed等国内外数据库中有关父亲职业性接触农药与儿童白血病关系的病例对照试验.按照一定的纳入和排除标准选取文献,采用RevMan5.3软件对文献进行Meta分析.结果 最终选取的10项病例对照试验,Meta分析结果显示:父亲职业接触农药儿童急性白血病患病率的危险性是不接触的1.52倍(OR=1.52,95％CI:1.17～1.96).以对照来源、研究时间、样本量及接触农药种类进行分组,亚组
Wire electrical discharge machining (wire-EDM) is an energy-intensive process,and its success relies on a correct selection of cutting parameters.It is vital to optimize energy consumption,along with productivity and quality.This experimental study optimi
The machining of hard-to-cut materials with a high degree of precision and high surface quality is one of the most critical considerations when fabricating various state-of-the-art engineered components.In this investiga-tion,a comprehensive three-dimensi